This work presents comprehensive observational evidence on how sharp vegetation contrasts between irrigated oases and deserts can affect local and regional weather. Hetao irrigation district, a 769,333-ha wide World Heritage Irrigation Structure in Inner Mongolia, China, illustrates how humanity's biggest hydraulic engineering project becomes a storm generator through enhancing vegetation contrast with its adjacent extensive deserts. Based on radar data collected during warm seasons from 2012 to 2023, this study explores the evolution, diurnal variation, organization, and movement of convective systems (CSs) initiated by boundary layer convergence lines that formed due to vegetation contrast between the irrigated oasis and adjacent Kubuqi and Ulan Buh deserts in different synoptic patterns in the Hetao area. A total of 228 CSs formed primarily along vegetation contrast lines in arid areas under synoptic patterns featuring adequate moisture and substantial instability, with similar to 35% exhibiting linear organization and similar to 20% propagating far downstream. These features were also compared across the borders between the Oasis and the Kubuqi Desert versus the Ulan Buh Desert, which have different sharpness of vegetation heterogeneity. Due to the sharper vegetation contrast, CSs over the Kubuqi Desert were nearly 11.7 times more prevalent with a higher prevalence of stronger linear organizational mode, greater intensity, and more frequent downstream propagation than those over the Ulan Buh Desert with a less sharp vegetation gradient, where stronger cellular organizational mode was dominant. These findings hold important implications for the nowcasting of severe weather in the semiarid Inner Mongolia and potentially in other desert-oasis border regions worldwide.